> > You don't have an external SCSI-case lying around?  I scrapped together
> > that and an old SCSI-CDROM drive, worked well.
>
> yep... trying this right now because booting from the internal CD-Rom
> drive in the 400 didn't work either:

Ok, I opened up the case of one of the model 300s and attached the CD-Rom
drive internallyt, because I don't have an MMJ adaptor to attach a serial
terminal to the model 400.

now booting from the CD gives the following output:

>>> boot dka600

...

Boot flags: 0,0
8084388+227040@@@@@@@@@lseek section headers: invalid file offset
@@@@@@@@@@open netbsd.gz: Input/output error
@@@@@@@@@@open netbsd.bak: Input/output error
@@@@@@@@@@open netbsd.bak.gz: Input/output error
@@@@@@@@@@open netbsd.old: Input/output error
@@@@@@@@@@open netbsd.old.gz: Input/output error
@@@@@@@@@@open onetbsd.gz: Input/output error
@@@@@@@@@@open onetbsd.gz: Input/output error
@@@@@@@@@@open netbsd.alpha: Input/output error
@@@@@@@@@@open netbsd.alpha.gz: Input/output error

Boot failed! Halting...

?05 HLT INSTR
  PC= 00000000.20000038 PSL= 00000000.00000007

>>>

Does this mean the CD hasn't been written correctly?
(I've written the cdhdtape disk image to it using cdrecord on linux)

--Lieven